The proposed research will utilize clinical data to quantitate the acute and long-term toxicity of all drugs commonly used in medicine. The procedures for data collection have been used and found to be effective for ten years. Monitors stationed on hospital wards collect information in a standardized fashion on patient characteristics, drug exposures, the development of clinical complications and final diagnoses. These data are computerized and retrievable in different formats. For patients with medical illnesses, data on 50,000 hospitalized patients are already on hand and available for analysis. Additional data on patients with surgical illnesses are being collected utilizing a system of data collection similar to that used for medical patients. The data allow for the quantitation of the relationships of outpatient drug use to diseases such as cancer, coronary heart disease, renal failure and bone marrow depression. In addition, rates of acute toxicity together with details of type, severity and populations at greatest risk for all commonly used drugs can be estimated. The ultimate goal is to provide practicing physicians with reasonably precise quantitative data on the toxicity of all commonly used drugs so that they may practice therapeutics on a more rational basis.